immune to attack; incapable of being tampered with;
"an impregnable fortress"
"fortifications that made the frontier inviolable"
"a secure telephone connection"
capable of conceiving
incapable of being overcome, challenged or refuted;
"an impregnable argument"
- They will establish impregnable fortresses.
- The lofty walls of the castle seemed impregnable.
- The lawyer won his case with an impregnable argument.
- Only in this way can you be in an impregnable position for good.
The Schloss Adler is inaccessible and impregnable. It would require a battalion of paratroops to take it.出自： A. MacLean
She carries within an impregnable conviction of being lovable.出自： A. Storr